The current method for dissolving carbon dioxide (CO2) into beer is to place diffusers at the bottom of a pressurized carbonation tank and bubble CO2 gas through the diffusers into the beer. The gas dissolves into the beer as the bubbles rise through the beer. A gas headspace is maintained at the top of the carbonation tank above the beer to collect and vent undissolved CO2. The source of the CO2 is typically commercially purchased storage dewars containing liquid CO2. The CO2 is vaporized into a gas and pressurized. Approximately half or more of the gas passing through the beer does not dissolve and is vented to the air outside the carbonation tank. When CO2 gas is added to the carbonation tank, the CO2 that is dissolved does not add volume to the tank and therefore does not increase pressure inside the carbonation tank. CO2 gas that is not dissolved will add volume to the tank and will increase pressure in the tank if not vented. Therefore, when using the current carbonation method, the carbonation tank must be continually vented to maintain the desired pressure. The pressure in the carbonation tank is used to control the final, saturated dissolved CO2 content of the beer. As the pressure of the gas and beer is increased, the beer can hold more dissolved CO2. Dissolved CO2 content is an important quality parameter for beer to provide the fizz, proper mouth feel, and flavor. Typical carbonation tank pressures range from 10 to 15 psi gauge and this allows the beer to increase CO2 concentration from typically 1 vol CO2/volume beer to 2.5 to 3 vol CO2/volume beer (vol/vol). Undissolved CO2 exiting the carbonation tank is a wasted cost, can increase the CO2 concentration in the building which creates a health hazard and requires additional cost for ventilation, and also adds to the greenhouse gas carbon footprint of the process. Also, the gas headspace at the top of the carbonation tank can allow oxygen from air into the tank upon initially filling the carbonation tank with beer. This oxygen can have detrimental effects on beer quality and reduce shelf life of packaged beer. The rate that the CO2 dissolves into the beer depends on the CO2 gas transferring from the bubble to the beer and varies greatly with the type of beer being carbonated, bubble size, pressure, and desired final CO2 content. These parameters can change from batch to batch.
It would therefore be desirable to develop an apparatus and method of carbonating beverages that overcomes these drawbacks.